1. Field of the Invention
The present invention relates to a method and apparatus for the subsequent underground sealing of an area, preferably of a dump, according to which a sheet-like sealing compound is introduced in the region outside the dump.
2. Description of the Prior Art
Dumps are places for depositing waste products of all types. As regards endangering human beings and the environment, these waste materials may contain harmful substances which may be brought into circulation by seepage water, leakages, erosion, or the method of introduction, and may pass through the earth into the water table. Many dumps were not adequately and promptly protected against an influence of the water table and a contamination of the soil, so that it was subsequently necessary to clean them up. The cleaning-up measures can be divided into three main groups:
(a) the transfer of the old deposits to an orderly, i.e. sealed, dump,
(b) encapsulation by covering and vertical and horizontal subsequent sealing, and
(c) hydraulic cleaning-up measures.
The transfer of the old deposits generally involves high costs, and the question arises as to whether excavation of the actual old deposits is sufficient, or whether or not the contaminated subsoil must also be excavated.
Known hydraulic cleaning-up measures are the diversion of the water table or ground water by vertical guide walls, the lowering of the water table level, the removal of the ground water in order to alter the flow, and the provision of protective wells. However, these measures require high operating costs, and with permeable earth generally do not guarantee any reliable protection from moving harmful substances, which move toward the water table.
Known and proven methods exist for encapsulation by covering and vertical sealing. However, no developed measures are available for the horizontal underground sealing. Horizontal sealing by injected sealing surfaces, which are introduced by way of vertical bores at intervals of one to three meters, has the essential drawback that it is necessary to bore through the dump body; thus, stationary harmful substances are brought into circulation, and can be fed through the bore hole directly to the water table.
An object of the present invention is to provide a method and apparatus for the complete in particular horizontal, sealing of dumps, according to which the dump body remains completely undisturbed, and subsequent encapsulation of old deposits which are harmful to the environment is possible.